Works in the public domain are those whose intellectual property rights have expired,1 have been forfeited,2 or are inapplicable. Examples include the works of Shakespeare and Beethoven, most of the early silent films, the formulae of Newtonian physics, and powered flight.1 The term is not normally applied to situations where the creator of a work retains residual rights, in which case use of the work is referred to as "under license" or "with permission".

As rights are country-based and vary, a work may be subject to rights in one country and not in another. Some rights depend on registrations with a country-by-country basis, and the absence of registration in a particular country, if required, implies public domain status in that country.

History

The term "public domain" did not come into use until the mid-17th century, although as a concept "it can be traced back to the ancient Roman Law, as a preset system included in the property right system."3 The Romans had a large proprietary rights system where they defined "many things that cannot be privately owned"3 as "res nullius", res communes, res publicae and res universitatis. The term "res nullius" was defined as things not yet appropriated.4 The term res commune was defined as "things that could be commonly enjoyed by mankind, such as air, sunlight and ocean."3 The term res publicae referred to things that were shared by all citizens, and the term res universitatis meant things that were owned by the municipalities of Rome.3 When looking at the public domain from a historical perspective, one could say the construction of the idea of "public domain" sprouted from the concepts of res commune, res publicae, and res universitatis in early Roman Law.3

When the first early copyright law was first established in Britain with the Statute of Anne in 1710, public domain did not appear. However, similar concepts were developed by British and French jurists in the eighteenth century. Instead of "public domain" they used terms such as publici juris or propriété publique to describe works that were not covered by copyright law.5 The phrase "fall in the public domain" can be traced to mid-nineteenth century France to describe the end of copyright term. The French poet Alfred de Vigny equated the expiration of copyright with a work falling "into the sink hole of the public domain"6 and if the public domain receives any attention from intellectual property lawyers it is still treated as little more than that which is left when intellectual property rights, such as copyright, patents, and trademarks, expire or are abandoned.7 In this historical context Paul Torremans describes copyright as a "little coral reef of private right jutting up from the ocean of the public domain."8 Because copyright law is different from country to country, Pamela Samuelson has described the public domain as being "different sizes at different times in different countries".9

Definition

Newton's own copy of his Principia, with hand-written corrections for the second edition

Definitions of the boundaries of the public domain in relation to copyright, or intellectual property more generally, regard the public domain as a negative space, that is, it consists of works that are no longer in copyright term or were never protected by copyright law.10 According to James Boyle this definition underlines common usage of the term public domain and equates the public domain to public property and works in copyright to private property. However, the usage of the term public domain can be more granular, including for example uses of works in copyright permitted by copyright exceptions. Such a definition regards work in copyright as private property subject to fair use rights and limitation on ownership.1 A conceptual definition comes from Lange, who focused on what the public domain should be: "it should be a place of sanctuary for individual creative expression, a sanctuary conferring affirmative protection against the forces of private appropriation that threatened such expression".10 Patterson and Lindberg described the public domain not as a "territory", but rather as a concept: "[T]here are certain materials – the air we breathe, sunlight, rain, space, life, creations, thoughts, feelings, ideas, words, numbers – `not subject to private ownership. The materials that compose our cultural heritage must be free for all living to use no less than matter necessary for biological survival."11 The term public domain may also be interchangeably used with other imprecise and/or undefined terms such as the "public sphere" or "commons", including concepts such as "commons of the mind", the "intellectual commons", and the "information commons".7

Value

Pamela Samuelson has identified eight "values" that can arise from information and works in the public domain.12:22

Possible values include:

Building blocks for the creation of new knowledge, examples include data, facts, ideas, theories, and scientific principle.

Access to cultural heritage through information resources such as ancient Greek texts and Mozart’s symphonies.

Promoting education, through the spread of information, ideas, and scientific principles.

Enabling follow-on innovation, through for example expired patents and copyright.

Enabling low cost access to information without the need to locate the owner or negotiate rights clearance and pay royalties, through for example expired copyrighted works or patents, and non-original data compilation.13

Promoting public health and safety, through information and scientific principles.

Promoting the democratic process and values, through news, laws, regulation, and judicial opinion.

Enabling competitive imitation, through for example expired patents and copyright, or publicly disclosed technologies that do not qualify for patent protection.12:22

Relationship with the Information Society

According to Bernt Hugenholtz and Lucie Guibault, the public domain is under pressure from the "commodification of information" as items of information that previously had little or no economic value have acquired independent economic value in the information age, such as factual data, personal data, genetic information, and pure ideas. The commodification of information is taking place through intellectual property law, contract law, as well as broadcasting and telecommunications law.12:1

Application to copyrightable works

Works not covered by copyright law

The underlying idea that is expressed or manifested in the creation of a work generally cannot be the subject of copyright law (see idea-expression divide). Mathematical formulae will therefore generally form part of the public domain, to the extent that their expression in the form of software is not covered by copyright.

Works created before the existence of copyright and patent laws also form part of the public domain. For example, the Bible and the inventions of Archimedes are in the public domain, but copyright may exist in translations or new formulations of these works.

Expiration of copyright

Determination of whether a copyright has expired depends on an examination of the copyright in its "source country".

In the United States, determining whether a work has entered the public domain or is still under copyright can be quite complex, primarily because copyright terms have been extended multiple times and in different ways—shifting over the course of the 20th century from a fixed-term based on first publication, with a possible renewal term, to a term extending to fifty, then seventy, years after the death of the author. The claim that "pre-1923 works are in the public domain" is correct only for published works; unpublished works are under federal copyright for at least the life of the author plus 70 years.

Legal traditions differ on whether a work in the public domain can have its copyright restored. In the European Union, the Copyright Duration Directive was applied retroactively, restoring and extending the terms of copyright on material previously in the public domain. Term extensions by the U.S. and Australia generally have not removed works from the public domain, but rather delayed the addition of works to it. However, the United States moved away from that tradition with the Uruguay Round Agreements Act, which removed from the public domain many foreign-sourced works that had previously not been in copyright in the US for failure to comply with US-based formalities requirements. Consequently, in the US, foreign-sourced works and US-sourced works are now treated differently, with foreign-sourced works remaining under copyright regardless of compliance with formalities, while domestically-sourced works may be in the public domain if they failed to comply with then-existing formalities requirements—a situation described as odd by some scholars, and unfair by some US-based rightsholders.26

Government works

Works of the United States Government and various other governments are excluded from copyright law and may therefore be considered to be in the public domain in their respective countries.27 In the United States, when copyrighted material is enacted into the law, it enters the public domain. Thus, e.g., the building codes, when enacted, are in the public domain.28 They may also be in the public domain in other countries as well. "It is axiomatic that material in the public domain is not protected by copyright, even when incorporated into a copyrighted work."29

Dedicating works to the public domain

Few if any legal systems have a process for reliably donating works to the public domain. They may even prohibit any attempt by copyright owners to surrender rights automatically conferred by law, particularly moral rights. An alternative is for copyright holders to issue a licence which irrevocably grants as many rights as possible to the general public, e.g., the CC0 licence from Creative Commons.30

Patents

In most countries the term for patents is 20 years, after which the invention becomes part of the public domain. In the United States, patents are good for 17 years upon approval.

Trademarks

A trademark registration may remain in force indefinitely, or expire without specific regard to its age. For a trademark registration to remain valid, the owner must continue to use it. In some circumstances, such as disuse, failure to assert trademark rights, or common usage by the public without regard for its intended use, it could become generic, and therefore part of the public domain.

Because trademarks are registered with governments, some countries or trademark registries may recognize a mark, while others may have determined that it is generic and not allowable as a trademark in that registry. For example, the drug "acetylsalicylic acid" (2-acetoxybenzoic acid) is better known as aspirin in the United States—a generic term. In Canada, however, "Aspirin", with an upper case A, is still a trademark of the German company Bayer, while aspirin, with a lower case "a" is not. Bayer lost the trademark in the United States, the UK and France after World War I, as part of the Treaty of Versailles. So many copy-cat products entered the marketplace during the war that it was deemed generic just three years later.31

Bayer also lost the trademark for "Heroin",where? which it trademarked a year before it trademarked Aspirin.citation needed